Anlotinib Hydrochloride: Multi-Target Tyrosine Kinase Inhibitor for Tumor Angiogenesis Research

Executive Summary: Anlotinib hydrochloride is a novel, small-molecule inhibitor that targets VEGFR2, PDGFRβ, and FGFR1, three key regulators of tumor angiogenesis, with nanomolar potency (Lin et al., 2018). This compound exhibits superior inhibitory activity against endothelial cell migration and tube formation compared to sunitinib, sorafenib, and nintedanib (Table 1). Anlotinib (hydrochloride) displays favorable pharmacokinetics, including high oral bioavailability and extensive tissue distribution. Safety data reveal a high LD₅₀ and mild toxicity profile, supporting its utility in advanced preclinical research. APExBIO supplies Anlotinib for research use, enabling reliable anti-angiogenic and signaling pathway studies in cancer models.

Biological Rationale

Angiogenesis is the process by which new blood vessels form from pre-existing vasculature. It is essential in both physiological (e.g., wound healing, embryogenesis) and pathological (notably tumorigenesis) contexts (Lin et al., 2018). Tumor cells secrete pro-angiogenic cytokines, including vascular endothelial growth factor (VEGF), platelet-derived growth factor-BB (PDGF-BB), and fibroblast growth factor 2 (FGF-2), to stimulate endothelial cell migration and the formation of new vasculature (Lin et al., 2018). Inhibiting these signaling pathways is a validated strategy for preventing tumor growth and metastasis. Small-molecule tyrosine kinase inhibitors (TKIs) that block VEGFR2, PDGFRβ, and FGFR1 are established agents in clinical and research oncology (product page).

Mechanism of Action of Anlotinib (hydrochloride)

Anlotinib hydrochloride (CAS 1058157-76-8) is a multi-target TKI that directly inhibits VEGFR2 (IC₅₀: 5.6 ± 1.2 nM), PDGFRβ (IC₅₀: 8.7 ± 3.4 nM), and FGFR1 (IC₅₀: 11.7 ± 4.1 nM) in concentration-dependent fashion (Lin et al., 2018). These kinases are central to angiogenic signaling in endothelial cells. Upon inhibition, downstream ERK pathway activation is attenuated, resulting in reduced endothelial proliferation, migration, and survival. Anlotinib blocks VEGF/PDGF-BB/FGF-2-induced capillary tube formation and cell migration in vitro, and suppresses vascular sprouting in ex vivo (rat aortic ring) and in vivo (chick CAM) assays (Lin et al., 2018). Mechanistically, anlotinib’s inhibition profile is broader and more potent compared to earlier TKIs such as sunitinib and sorafenib (compare: PD-0325901.com).

Evidence & Benchmarks

• Anlotinib inhibits VEGFR2, PDGFRβ, and FGFR1 autophosphorylation in endothelial cells at nanomolar concentrations (see Fig. 1B).
• In endothelial cell migration assays (EA.hy 926), anlotinib dose-dependently reduces VEGF-induced cell migration (IC₅₀ < 10 nM) (see Fig. 2).
• Capillary-like tube formation is significantly inhibited by anlotinib at concentrations >5 nM, outperforming sunitinib, sorafenib, and nintedanib (see Table 1).
• In rat aortic ring and CAM assays, anlotinib reduces microvessel density and vessel sprouting more effectively than comparator TKIs (in vivo evidence).
• Pharmacokinetic studies in rats and dogs show oral bioavailability of 28–58% and 41–77% respectively, with high plasma protein binding (93% in humans) (product data).
• Median lethal dose (LD₅₀) in 14-day oral studies is 1735.9 mg/kg, with no significant organ or genetic toxicity detected (product page).

Applications, Limits & Misconceptions

Anlotinib hydrochloride is primarily used in research applications focused on anti-angiogenic mechanisms, cell migration inhibition, and pathway modulation. It is suited for in vitro cellular assays (e.g., human vascular endothelial cells), ex vivo angiogenesis models, and preclinical tumor studies. The compound is not intended for diagnostic or therapeutic use in humans.

Researchers can refer to the Anlotinib (hydrochloride) product page (SKU C8688) from APExBIO for full specifications.

This article expands upon prior resources such as this overview by providing detailed comparative benchmarks and pharmacokinetic data. For advanced workflow guidance, see this workflow integration guide, which this article updates with newly published safety and absorption findings.

Common Pitfalls or Misconceptions

• Not suitable for clinical use: Anlotinib (hydrochloride) supplied by APExBIO is for research only; it is not approved for human or veterinary therapy.
• Does not inhibit all kinases: Activity is selective; kinases outside the VEGFR/PDGFR/FGFR axis are minimally affected in standard assays.
• Requires validated cell models: Efficacy may not translate across non-endothelial or non-tumor cell lines.
• Metabolite activity uncharacterized: While anlotinib is metabolized by CYP3A, the bioactivity of its metabolites may differ and is not fully defined in research protocols.
• Storage and handling: Degradation may occur if stored above -20°C; strictly follow manufacturer recommendations for stability (APExBIO).

Workflow Integration & Parameters

Anlotinib hydrochloride is routinely integrated into anti-angiogenic and signaling pathway inhibition assays. Standard protocols use concentrations ranging from 1 nM to 100 nM, depending on assay sensitivity. It is compatible with capillary tube formation, scratch (wound healing) migration, and phospho-ERK readouts. Pre-dilution in DMSO is recommended for aqueous applications. For pharmacokinetic modeling, note the high protein binding and broad tissue distribution, including CNS penetration.

For a comprehensive troubleshooting and workflow guide, readers may consult this APExBIO protocol resource, which this article augments with new comparative toxicity and absorption data.

Conclusion & Outlook

Anlotinib hydrochloride (APExBIO, SKU C8688) is a validated, potent multi-target tyrosine kinase inhibitor for research on tumor angiogenesis and tyrosine kinase signaling pathways. Its nanomolar activity against VEGFR2, PDGFRβ, and FGFR1, combined with a favorable safety and pharmacokinetic profile, make it a preferred reference compound for anti-angiogenic research. Ongoing studies will further define its translational potential and expand its application portfolio in cancer biology and vascular research.